Around the world, the conventional power plants and many industrial pulverized coal boilers burn heavy oil, diesel oil or natural gas, for the starting ignition and low-load combustion stabilization thereof, to achieve the ignition of pulverized coal. So in each year, a plenty of fuel oil is consumed. Recently, the developed plasma ignition and combustion stabilizing technique save fuel oil to a large extent and realize starting of pulverized coal boiler without oil. The Chinese patent CN03268412.6 discloses a staged igniting burner, as shown in FIG. 12, it comprises an external burning chamber 4, an igniting source (not shown), wherein a central chamber 1 is provided inside the external burning chamber 4, and n stages of internal burning chambers 2, 3, . . . , are provided between the central chamber 1 and the external burning chamber 4, the pulverized coal is ignited by the igniting source inside the central burning chamber 1, and the pulverized coal flame ignited in the central burning chamber 1 is used to ignite the pulverized coal inside the next stage of internal burning chamber 2, and then the pulverized coal inside the next burning chamber 3 is ignited accordingly stage by stage, and finally the pulverized coal inside the last stage of burning chamber 4 is ignited and then enters the furnace to take part in combustion.
The Chinese patent CN200720146244.6 discloses a plasma burner, as shown in FIG. 13, it comprises at least two stages of burning chambers 14, 16 as well as a plasma generator 31 for ignition of pulverized coal in the first stage burning chambers 14 of the at least two stages of burning chambers, wherein the flame of the pervious stage of burning chamber 14 ignites the pulverized coal in the next stage of burning chamber 16 or further burns with the supplemented air in the next stage of burning chamber 16, wherein the axial direction of the plasma generator is parallel to the direction in which the air-pulverized coal flow 32 enters the first stage of burning chamber 14, and at the same time is parallel to the axis of the burning chambers 14, 16.
The above patents discloses the multi-stage chamber structure of plasma pulverized coal burner which contains the following drawbacks: insufficient adaptability of the plasma pulverized coal burner to coal quality, air velocity and pulverized coal density, and insufficient ignition stabilization and reliability.